In order to achieve high integration and high speed of integrated circuits, such as ULSIs, used for computers, miniaturization of design rule of semiconductor devices has been progressed year by year. Because of this, the instances that tinier surface defects adversely affect performance of the semiconductor devices have been increased, and the importance of managing nano-scale defects which have not been acknowledged as a problem is increasing.
Surface defect inspection equipment is used for managing surface defects of a silicon wafer. The defects detected by the surface defect inspection equipment include foreign materials and residues, which could not be removed from a silicon wafer surface in a polishing process, a rinsing process, and a washing process. General surface defect inspection equipment is adapted to detect the presence or absence and the size of defects by irradiating a silicon wafer surface with light, such as laser light, and receiving and analyzing the reflected light as a signal.
When irradiating a mirror-finished silicon wafer surface after polishing or polishing and rinsing with intense light, in some cases, tarnish is observed by diffused reflection due to very fine roughness on the silicon wafer surface. The tarnish is called haze, and the haze can be used as a measure of roughness of a silicon wafer surface. When there is haze on a silicon wafer surface, diffused reflection light generated by the haze becomes noise and defect detection by surface defect inspection equipment may be prevented. Therefore, as the size of defects to be detected, that is, the size of defects to be managed becomes smaller, the necessity of improving a haze level is increasing.
Patent Document 1 discloses a polishing composition containing a nonionic surfactant of a copolymer of polyoxyethylene and polyoxypropylene for the main purpose of reducing haze on a silicon wafer surface after polishing. Patent Document 2 discloses a polishing composition containing polyoxyethylene sorbitan mono-fatty acid ester for the main purpose of reducing haze on a silicon wafer surface after final polishing. However, the haze reduction effect by the polishing compositions of Patent Documents 1 and 2 is not enough to manage nano-scale defects.